German Patent No. 44 09 172 A1 describes a mechanical AND element in which Bowden cables are prestressed by springs with respect to a coupling carriage. The device described therein requires that the spring forces be adjusted accurately.
German Patent No. 36 11 020 A1 describes another AND element, similar to the AND element described above, in which flexible transmission members are designed as wire trip elements that transmit compressive forces. The coupling carriage is displaced by a wire trip element for a first input signal and also serves as a carrier of the wire trip element for the second input signal. In this way, a complete stroke occurs at the output of the AND element only when both input signals are present. This type of operation, however, requires that the wire trip element for the second input signal be carried displaceably. Furthermore, careful adjustment of all wire trip elements is required to ensure that the wire trip element for the output signal is properly actuated and therefore that the desired action takes place only with a full stroke of the two wire trip elements for the input signals. For this reason, with the AND element described therein, a stepped intermediate lever is provided between the coupling carriages and the wire trip element for the output signal to change the transmission ratio.